Threshing Demonstration

T hreshing machines, originally known as "thrashing machines", were used in grain crop farming to cut the heads of grain off the straw, remove the grain from the heads, and sack the grain. It revolutionised the processing of grain crops when it was introduced in the late 1700s.

The first threshing methods involved beating grain by hand with a flail, or trampling it by animal hooves. Early threshing machines were powered by horses walking on a treadmill. Steam engines eventually replaced horsepower around the late 1800s. Like other inventions during the industrial revolution, the threshing machine replaced the work done by thousands of manual labourers. Many threshing machines were smashed during this period in protest.

Tomorra we’re gonna go to work. I seen thrashin’ machines on the way down. That means we’ll be buckin’ grain bags, bustin’ a gut.

John Steinbeck, "Of Mice and Men"

Today, combines – a combination of a harvester and thresher – have completely replaced threshing machines.

How Threshing Machines Work

In the first stage, bundles of grain and straw were pitched into the feeder (or hopper). The feeder controls the rate of feed passing into the machine to prevent overloading.

In the second stage, the separator, a rotating set of blades, tear the bundles apart, breaking the twine and snapping the heads from the straw. They then beat the straw and heads onto a grooved plate, knocking kernels from the heads without crushing them. The straw then passes over a rack that removes most of the straw from the kernels. Whatever passes through falls onto a series of progressively smaller shaking screens, removing most of the remaining straw and chaff from the kernels.

In the final stage stage, the kernels that pass through the last screen are moved over a stream of air that blow the remaining straw and chaff away. The cleaned kernels then fell into sacks. The straw and chaff were blown out onto the straw stack.

As I walked down the road on this fine autumn morn'
I can see the great combine collecting the corn
And my mind wanders back in a moment of joy
To the day of the thresher when I was a boy

All over the valley you could hear the strange sound
Of that mighty machine on its annual round
All the men in the town land would follow at will
And they'd all lend a hand with the old threshin' mill

So boil up the bacon and the cabbage that's green
Have plenty of spuds laced with butter between
For eight empty bellies will soon need a fill
For it makes a man hungry, the old threshing mill